Piezoelectric
multilayers can achieve both piezoelectric and triboelectric
generation simultaneously by the deformation and contacting–separating
process between upper and lower surfaces of adjacent layers. The electrospun
poly(vinylidene fluoride) (PVDF) fiber film as a type of piezoelectric
multilayer with abundant inner surfaces can generate both large piezoelectric
and triboelectric signals. However, in most studies on the piezoelectric
fiber films, the high-generation performances are attributed to the
piezoelectric properties and their triboelectric contribution is usually
ignored. Thus, the contributions of triboelectricity in piezoelectric
multilayers should be considered, and a highly effective hybrid nanogenerator
needs to be designed by achieving the synergy of triboelectricity
and piezoelectricity. Herein, a head-to-head parallel assembly was
used in a PVDF multilayer generator to improve the electricity output,
and the respective contributions and synergistic effect of triboelectricity
and piezoelectricity in multilayer generators were studied. The maximum
open-circuit voltage, short-circuit current, and charge values of
the designed hybrid nanogenerator device were 150 V, 7 μA, and
100 nC, respectively. Then, the head-to-head parallel assembly method
was used for electrospun poly(vinylidene fluoride-co-trifluoroethylene) fiber films, and the output performance was shown
to be about 4 times that obtained by the normal series connection.
This head-to-head parallel assembly can be used as a common harvesting
method to collect piezoelectric and triboelectric energy effectively
from piezoelectric multilayers.